AmerzoneBroken Sword 1: Shadow of the TemplarsDay of the TentacleGabriel Knight 1: Sins of the FathersGrim FandangoKeepsakeThe Longest JourneyMorpheusMyst/RealMystObsidianReturn to Mysterious IslandSanitariumSecret of Monkey IslandTimelapseUru

Flotsam very kindly allowed me 2 more votes since Agon series is considered 1 game. I am a little chary of voting for the older games as The List is intended as a guide to recommended games. Some of the older games are getting extremely hard to get these days.